Patlak联合不可逆两组织隔室模型动态18F-FDG PET/CT诊断肺原发肿瘤胸部高代谢转移性淋巴结

目的 观察Patlak联合不可逆两组织隔室模型（2TC-3k）动态¹⁸F-FDG PET/CT诊断肺原发肿瘤胸部高代谢转移性淋巴结的价值。方法 前瞻性纳入16例CT显示胸部存在可疑淋巴结转移且拟接受PET/CT检查的肺原发肿瘤患者，行胸部动态和全身静态¹⁸F-FDG PET/CT扫描；计算全身静态PET/CT图像中原发肿瘤及胸部高代谢淋巴结的最大标准摄取值（SUV_max）及平均标准摄取值（SUV_mean），纳入淋巴结SUV_max>2.5者。采用Patlak图形分析和2TC-3k分析原发肿瘤和高代谢淋巴结动态数据，获取动力学参数的一阶特征参数，建立logistic模型；以病理学为金标准，分析模型诊断胸部高代谢淋巴结转移的效能。结果 共纳入11例患者、32枚胸部高代谢淋巴结，病理学示15枚为转移性、17枚非转移性。Ki_Kurtosis诊断胸部转移性高代谢淋巴结的曲线下面积（AUC）为0.81，以71 590.45为Ki_Kurtosis的截断值，其敏感度为70.60%，特异度为86.70%；V_B_Entropy的AUC为0.79，以6.16×10^－4为V_B_Entropy的截断值，其敏感度为80.00%，特异度为82.40%。肺原发肿瘤与胸部高代谢转移性淋巴结V_B_Kurtosis （r=0.67，P<0.05）和Ki_UPP （r=0.69，P<0.05）呈正相关。Patlak动态PET/CT模型诊断胸部转移性高代谢淋巴结的AUC为0.85[95%CI（0.71，0.99）]，敏感度为76.50%，特异度为93.30%；2TC-3k动态PET/CT模型的AUC为0.87[95%CI（0.74，0.99）]，敏感度为82.40%，特异度为80.00%；二者联合模型的AUC为0.91[95%CI（0.80，1.00）]，敏感度为94.10%，特异度为80.00%；3个模型AUC两两比较差异均无统计学意义（P均>0.05）。结论 Patlak结合2TC-3k动态¹⁸F-FDG PET/CT对诊断肺原发肿瘤胸部高代谢转移性淋巴结具有一定价值。

Patlak combined with irreversible two-tissue compartment model dynamic 18F-FDG PET/CT for diagnosis of hypermetabolic thoracic metastatic lymph nodes of primary lung tumor

Objective To observe the value of Patlak combined with irreversible two-tissue compartment model (2TC-3k) dynamic ¹⁸F-FDG PET/CT for diagnosis of hypermetabolic thoracic metastatic lymph nodes of primary lung tumor.Methods Totally 16 patients with suspected thoracic lymph node metastasis who would undergo PET/CT were prospectively enrolled. Chest dynamic and whole-body static ¹⁸F-FDG PET/CT scanning were performed. The maximum standard uptake value (SUV_max) and the mean standard uptake value (SUV_mean) of primary tumor and hypermetabolic thoracic lymph nodes on whole-body static PET/CT images were calculated, and patients with SUV_max of lymph node >2.5 were enrolled. Patlak graphic analysis and 2TC-3k were used to analyze dynamic data of primary tumor and hypermetabolic lymph nodes to obtain the first-order characteristic parameters of each kinetic parameter, and then logistic models were established. Taken pathology as the gold standards, the efficacy of logistic models for diagnosing hypermetabolic thoracic lymph node metastasis were analyzed.Results A total of 11 patients with 32 hypermetabolic thoracic lymph nodes were enrolled. Pathology showed 15 metastatic and 17 non metastatic lymph nodes. The area under the curve (AUC) of Ki_Kurtosis for diagnosing hypermetabolic thoracic metastatic lymph nodes was 0.81. Taken 71 590.45 as the cut-off value of Ki_Kurtosis, the sensitivity was 70.60% and the specificity was 86.70%. AUC of V_B_Entropy was 0.79.Taken 6.16×10^-4 as the cut-off value of V_B_Entropy, the sensitivity was 80.00% and the specificity was 82.40%. Both V_B_Kurtosis (r=0.67, P<0.05) and Ki_UPP (r=0.69, P<0.05) of primary lung tumors were positively correlated with those of hypermetabolic thoracic metastatic lymph nodes. AUC of Patlak dynamic PET/CT model for diagnosing hypermetabolic thoracic metastatic lymph nodes was 0.85[95%CI(0.71, 0.99)], with sensitivity of 76.50% and specificity of 93.30%, while of 2TC-3k dynamic PET/CT model was 0.87[95%CI(0.74, 0.99)], with sensitivity of 82.40% and specificity of 80.00%. AUC of the combined model of Patlak and 2TC-3k was 0.91[95%CI(0.80, 1.00)], the sensitivity and specificity was 94.10% and 80.00%, respectively. There was no significant difference of AUC between each 2 models (all P>0.05).Conclusion Patlak combined with 2TC-3k dynamic ¹⁸F-FDG PET/CT had a certain value for diagnosis of hypermetabolic thoracic metastatic lymph nodes of primary lung tumor.